Polls have narrowed in recent weeks but Merkel's CDU still maintain an edge.

German Chancellor Angela Merkel's conservative bloc has edged a small lead in a new poll over their main centre-left rivals with just over six months until federal elections.

The poll, by Forschungsgruppe Wahlen and for broadcaster ZDF, placed the CDU / CSU bloc on 34 points, just two ahead of the SPD who have enjoyed a surge in support over recent weeks.

Merkel and the centre-left SPD candidate Martin Schulz, who has boosted the party's fortunes since being nominated in January, were neck-and-neck in the personal popularity stakes, with both achieving 44% support.

The popularity poll was a major boost to Chancellor Merkel who in the same poll in February was 11 points behind Schulz.

Mr Schulz who was the President of the European Parliament from 2012 until January this year, has helped the SDP to a surge in the polls since announcing his candidacy to be chancellor, taking the party from almost 15 points behind Merkel's conservative bloc in mid-January, to leading some polls.

Support overall for the SDP has now reached its highest point for more than five years, but the difficulty will be in maintaining strong polling numbers if the 'Schulz-effect' wears off.

Schulz has campaigned to deal with social justice and revise labour market reforms that were introduced by former SPD chancellor Gerhard Schröder over a decade ago.

Four in a row?

Angela Merkel is attempting to win the chancellorship for a fourth consecutive time after leading a grand coalition along with the SDP in 2005, a conservative-FDP coalition in 2009 and a second grand coalition that was formed in 2013.